mirror of
https://github.com/abseil/abseil-cpp.git
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108 lines
3.4 KiB
C++
108 lines
3.4 KiB
C++
// Copyright 2025 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "absl/strings/internal/generic_printer.h"
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#include <cstddef>
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#include <cstdlib>
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#include <ostream>
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#include <string>
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#include "absl/base/config.h"
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#include "absl/strings/ascii.h"
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#include "absl/strings/escaping.h"
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#include "absl/strings/str_format.h"
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namespace absl {
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ABSL_NAMESPACE_BEGIN
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namespace internal_generic_printer {
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// Out-of-line helper for PrintAsStringWithEscaping.
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std::ostream& PrintEscapedString(std::ostream& os, absl::string_view v) {
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return os << "\"" << absl::CHexEscape(v) << "\"";
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}
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// Retuns a string representation of 'v', shortened if possible.
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template <class T, class F>
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std::string TryShorten(T v, F strtox) {
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std::string printed =
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absl::StrFormat("%.*g", std::numeric_limits<T>::max_digits10 / 2, v);
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T parsed = strtox(printed.data());
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if (parsed != v) {
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printed =
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absl::StrFormat("%.*g", std::numeric_limits<T>::max_digits10 + 1, v);
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}
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return printed;
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}
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// Out-of-line helpers for floating point values. These don't necessarily
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// ensure that values are precise, but rather that they are wide enough to
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// represent distinct values. go/c++17std/numeric.limits.members.html
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std::ostream& PrintPreciseFP(std::ostream& os, float v) {
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return os << TryShorten(v, [](const char* buf) {
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char* unused;
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return std::strtof(buf, &unused);
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}) << "f";
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}
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std::ostream& PrintPreciseFP(std::ostream& os, double v) {
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return os << TryShorten(v, [](const char* buf) {
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char* unused;
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return std::strtod(buf, &unused);
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});
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}
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std::ostream& PrintPreciseFP(std::ostream& os, long double v) {
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return os << TryShorten(v, [](const char* buf) {
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char* unused;
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return std::strtold(buf, &unused);
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}) << "L";
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}
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// Prints a nibble of 'v' in hexadecimal.
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inline char hexnib(int v) {
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return static_cast<char>((v < 10 ? '0' : ('a' - 10)) + v);
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}
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template <typename T>
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static std::ostream& PrintCharImpl(std::ostream& os, T v) {
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// Specialization for chars: print as 'c' if printable, otherwise
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// hex-escaped.
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return (absl::ascii_isprint(static_cast<unsigned char>(v))
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? (os << (v == '\'' ? "'\\" : "'") << v)
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: (os << "'\\x" << hexnib((v >> 4) & 0xf) << hexnib(v & 0xf)))
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<< "' (0x" << hexnib((v >> 4) & 0xf) << hexnib(v & 0xf) << " "
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<< static_cast<int>(v) << ")";
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}
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std::ostream& PrintChar(std::ostream& os, char c) {
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return PrintCharImpl(os, c);
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}
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std::ostream& PrintChar(std::ostream& os, signed char c) {
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return PrintCharImpl(os, c);
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}
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std::ostream& PrintChar(std::ostream& os, unsigned char c) {
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return PrintCharImpl(os, c);
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}
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std::ostream& PrintByte(std::ostream& os, std::byte b) {
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auto v = std::to_integer<int>(b);
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os << "0x" << hexnib((v >> 4) & 0xf) << hexnib(v & 0xf);
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return os;
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}
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} // namespace internal_generic_printer
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ABSL_NAMESPACE_END
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} // namespace absl
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